Clarke

ABSTRACT

A METHOD OF MAKING A PRESSED ARTICLE INCLUDING THE STEP OF PRESSING A WORKING PIECE AND AT LEAST ONE RESILIENT LIQUID-FILLED CUSHION PLATE BETWEEN THE PLATENS OF A PRESS AND HEATING, OR OPTIONALLY COOLING, THE WORKPIECE AND CUSHION PLATE DURING THE PRESSING OPERATION IS DISCLOSED. THE PRESSING OPERATION IS ACCOMPLISHED SUCH THAT THE VOLUME OF LIQUID IN THE CHAMBER OF THE CUSHION PLATE IS MAINTAINED SUBSTANTIALLY CONSTANT BY PROVIDING MEANS RESPONSSIVE TO THE PRESSURE WITHIN THE CUSHION PLATE TO ACCEPT THE INCREASE IN VOLUME OF LIQUID BROUGHT ABOUT BY THE THERMAL EXPANSION OF THE LIQUID FILLING THE CHAMBER IN THE HEATED EMBODIMENT, OR TO INTRODUCE ADDITIONAL LIQUID INTO THE CLOSED CHAMBER WHEN THE PRESSING IS CONDUCTED AND THE WORKPIECE IS COOLED. THE DISCLOSED RESILIENT CUSHION PLATE INCLUDES A PAIR OF CONTINUOUS METAL SHEETS SPACED APART FROM EACH OTHER IN A SUBSTANTIALLY PARALLEL MANNER, AT LEAST ONE OF SHEETS BEING RELATIVELY THIN AND FLEXIBLE. THE SHEETS ARE SEALED TOGETHER AROUND THEIR PERIPHERIES TO DEFINE AN INNER CHAMBER WHICH CAN BE COMPLETELY FILLED WITH A LIQUID AND THE PLATE IS PROVIDED WITH AN ENTRANCE LEADING INTO THE CHAMBER POSITIONED SO AS TO NOT INTERFERE WITH THE PRESSING OPERATION. THE ENTRY PORT PERMITS THE FILLING OF THE CHAMBER WITH LIQUID AND PROVIDES FOR COMMUNICATION TO AND FROM THE CHAMBER FOR ACCOMMODATING THE EXPANSION OR CONTRACTION OF LIQUID WITHIN THE CHAMBER, DEPENDING UPON PRESSING CONDITIONS. THE INVENTION IS PARTICULARLY ADAPTED FOR PRESSING SHEETS OF PLASTIC MATERIALS AND AN APPARATUS FOR CONDUCTING THE METHOD IS ALSO DESCRIBED.

DEFENSIVE PULTCATION UNITED STATES PATENT AND TRADEMARK OFFICE Publishedat the request of the applicant or owner in accordance with the Noticeof Dec. 16, 1969, 869 0.G. 687. The abstracts of Defensive Publicationapplications are identified by distinctly numbered series and arearranged chronologically. The heading of each abstract indicates thenumber of pages of specification, including claims and sheets ofdrawings contained in the application as originally filed. The files ofthese applications are available to the public for inspection andreproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent and Trademark Office makes noassertion as to the novelty of the disclosed subject matter.

PUBLISHED OCTOBEP 7, 1975 T939,001 PRESSING Kenneth Clarke, Knebworth,and Thomas Alfred Stanley, Welwyn Garden City, England, assignors toImperial Chemical Industries Limited, London, England Filed Oct. 30,1972, Ser. No. 301,727 Claims priority, application Great Britain, Nov.5, 1971, 51,487/71 Int. Cl. 1330b 15/34; B02c 11/08 US. Cl. IOU-38 4Sheets Drawing. 42 Pages Specification A method of making a pressedarticle including the step of pressing a workpiece and at least oneresilient liquid-filled cushion plate between the platens of a press andheating, or optionally cooling, the workpiece and cushion plate duringthe pressing operation is disclosed. The pressing operation isaccomplished such that the volume of liquid in the chamber of thecushion plate is maintained substantially constant by providing meansresponsive to the pressure within the cushion plate to accept theincrease in volume of liquid brought about by the thermal expansion ofthe liquid filling the chamber in the heated embodiment, or to introduceadditional liquid into the closed chamber when the pressing is conductedand the workpiece is cooled.

The disclosed resilient cushion plate includes a pair of continuousmetal sheets spaced apart from each other in a substantially parallelmanner, at least one of the sheets being relatively thin and flexible.The sheets are sealed together around their peripheries to define aninner chamher which can be completely filled with a liquid and the plateis provided with an entrance leading into the chamber positioned so asto not interfere with the pressing operation. The entry port permits thefilling of the chamber with liquid and provides for communication to andfrom the chamber for accommodating the expansion or contraction ofliquid within the chamber, depending upon pressing conditions. Theinvention is particularly adapted for pressing sheets of plasticsmaterials and an apparatus for conducting the method is also described.

Oct. 7, 1975 K.CLARKE et a1. T939,001

PRESSING Original Filed Oct. 30, 1972 Sheet 1 of 3 Oct. 7, 1975 K.CLARKEet a1.

PRESSING Sheet 2 of 3 Original Filed Oct. 30, 1972 Oct. 7, 1975 K.CLARKEet a1.

PRESSING Original Filed Oct. 30, 1972 Sheet 3 of 3

